In the paper we deal with the problem of optimal partitioning of a traffic demand polytope using a hyperplane. In the considered model all possible demand matrices belong to a polytope. The polytope can be divided into parts, and different routing schemes can be considered while dealing with traffic matrices from different parts of the polytope. The model can be applied to all networks that support unrestricted routing of bifurcated flows, e.g., MPLS networks or optical networks. In the paper we present an algorithm that solves one of the most practical versions of the considered problem, i.e., reservation vectors on both sides of the hyperplane have to be the same. Moreover, we present another (faster) algorithm that solves a more restricted version of the problem. Finally, we present numerical results proving the applicability of the introduced algorithms